1. Field of the Invention
The present invention relates to a numerical controller which is compact and capable of providing a variety of functions.
2. Discussion of the Related Art
In a conventional numerical controller, a control section and an application section are integrated as a single unit. The control section is used for controlling a machine. The application section is used for inputting data into the control section, as well as for displaying a control status and other items. Such a conventional numerical controller allows a machine operator or a maintenance person to perform switching among a plurality of screens in order to perform various kinds of work. Also, on its control panel, the numerical controller has a keyboard for inputting data into the control section and a large display for displaying a detailed control status.
The numerical controller stores therein an NC program suitable for a machine to be controlled, as well as a system program required for execution of the NC program. Through replacement of the NC program, the numerical controller can control the machine in accordance with the shape of a workpiece.
The numerical controller also stores an abnormality diagnosis program. When an abnormality occurs during operation, the abnormality diagnosis program is executed in order to diagnose the abnormality, and the result of the diagnosis is displayed on the large display.
As described above, since the operation panel of the conventional numerical controller is provided with the keyboard and the large display, which the machine operator does not use in the course of ordinary operations, the size of the numerical controller cannot be reduced. In addition, when a plurality of machine tools are to be controlled, a plurality of numerical controllers must be used, inevitably resulting in an increase in the number of keyboards and displays that are not used in the course of ordinary operations.
Moreover, when after the installation of a machining system with a numerical controller, another machining system with a numerical controller having a new function is added, there occurs a problem that the new function can be used in one numerical controller but cannot be used in the other numerical controller. In order to allow the numerical controller not supporting the new function to execute an NC program which requires the numerical controller to have a system program for the new function, the system program for the new function must be installed to the numerical controller. However, since the system program is usually stored in a ROM, the operation for installing the system program for the new function into the ROM is complex. Especially, when there are a plurality of numerical controllers, the system program for the new function must be installed to each of the numerical controllers, so that the installation operation becomes troublesome.
Moreover, in the case where an abnormality diagnosis program is stored in the numerical controller, a memory having a large capacity must be used for storing the diagnosis program, because the diagnosis program is composed of many diagnosis subprograms corresponding to various kinds of conditions. When a plurality of numerical controllers are used, a memory having a large capacity must be provided in each numerical controller.